1. Field of the Invention
The present invention relates to a band storing machine for temporarily storing band-like material in a continuously operating process line, for example by the supply of sheet metal in band-like form to tube welding machines. The band storing machine has two concentrically arranged roller baskets or cages for winding up the band; withdrawal of the band is effected via a lateral displacement guide disposed in the inner basket.
The purpose of band storing machines is to made possible the stationary connection of the next band to the end of the preceding band without having to halt the operation of the processing line. In the steel and nonferrous metal industry, this involves welding a new coil onto the end edge of a coil which is in the process of being processed, for example in the manufacture of straight bead welded tubes. The preparation of the band ends, and the welding on of a new coil, requires approximately 2-4 minutes during which the joint and welding area are essentially not allowed to be moved.
2. Description of the Prior Art
Heretofore known band storing machines are in the form of loop-forming pits, loop-forming structures, or loop-forming carriages. One of the drawbacks of such heretofore known band storing machines is that they require a large amount of space.
Also known is a band storing machine having horizontal band guidance, i.e. the band is supported in the storing machine on a horizontal edge. The storing machine thus has the form of an upright cylinder in which the band forms a spiral. A so-called called pusher is provided to transport the band; the so-called pusher effects a feeding action by pushing the band into the cylinder. This requires an appropriate stiffness of the band material, so that the band must have a certain minimum thickness. A further drawback of this device is that the supporting band edge is often damaged and that relative movements occur between the individual band windings.
A number of the drawbacks of the aforementioned known band storing machines are avoided by a machine which has become known as a free loop band storing machine. This type of machine includes the initially mentioned general features, namely two concentrically arranged roller baskets, which with this heretofore known machine are rigidly disposed about a horizontal central axis, so that what is involved is a horizontal drum which cannot, however, move on its own. Here, too, the band is pushed into the storing machine by means of a pusher, and in particular initially onto the inside of the outer roller basket, where it forms a band winding which increases toward the outside. From there, the band passes via a freely rotating band loop to the outer side of the inner roller basket, where it similarly forms a band winding. The band leaves the storing machine via the lateral displacement guide which is disposed in the inner basket, and from there passes to the processing machine. This heretofore known type of band storing machine has a relatively great storage capacity relative to the room which it requires. However, a drawback to this known machine is that it still requires the pushing feed of the band into the storing machine. Under certain band characteristics, there is not possible to avoid compression of the band or to prevent the band from breaking away to the side. Furthermore, with fin bands there exists the danger that the outer band winding, in the upper region of the outer basket, will drop down under its own weight, thus obstructing the freely rotating band loop.
An object of the present invention is to provide a band storing machine of the aforementioned general type in which the band is transported by being pulled, and on the whole is handled particularly gently. At the same time, the advantage of a large storage capacity in a small amount of space should be maintained.